A servomotor is a rotary actuator comprising a rotational shaft, a motor to rotate the shaft, and a sensor to detect the position of the shaft. Servomotors are used in a variety of applications, including applications related to radio-controlled (RC) vehicles. For example, servomotors can be used to control steering mechanisms for (i) RC cars and trucks (turning wheels right or left), (ii) RC planes (positioning wing flaps and rudders), (ii) RC helicopters (positioning swash-plates and tail rudders), and (iii) other similar RC vehicle applications.
In operation, a servomotor receives a control signal that represents a desired rotational position of the shaft. The control signal may be analog or digital depending upon the design of the servomotor. In response to the control signal, the servomotor applies power to the motor to rotate the shaft to the desired position. The shaft typically rotates about +/−60° (120° total) around an axis of rotation, but the actual range of rotation can vary depending upon the design of the servomotor and its intended application. The sensor (e.g., a potentiometer or similar sensor) detects the actual rotational position of the shaft which can be fed back through a control loop for setting the rotational position of the servomotor shaft.